新型多条多气隙阻性板探测器的性能测试

Measurement of New Type Multi-strip Multi-gap Resistive Plate Chambers

为提高德国FOPI系统飞行时间的探测本领，运用新型多条多气隙阻性板探测器对FOPI系统进行升级改造。探测器的制作已完成，为保证探测器的质量，对它们进行了一系列的测量和质量确认。测试结果证明，系统的本底计数率分布在0．2Hz／cm^2附近，工作高压9．6kV；利用7射线放射源测试，时间分辨（包括闪烁体的时间分辨）分布在220-280ps之间；采用质子束流测量，其探测效率可达98％以上，时间分辨可达75ps。

The production of the multi-strip multi-gap resistive plate chambers for FOPI＇s Time-of-Flight （TOF） upgrade was accomplished. In order to assure the timing performance and quality of all detectors in the mass production, a quality assurance chain for the counters was implemented. First, the high-voltage （HV） test was performed to assure its HV-stability up to 11 kV （125 kV/cm） and to determine the dark rates of the detectors. Then, the performance of all counters with calibrated electronics was tested using a gamma source and proton beam. For proton beam, the timing resolution of MMRPC can reach to 75 ps, and the efficiency can be better than 98%.